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Hydroxypinacolone retinoate (HPR) serum OEM/ODM manufacturing
Hydroxypinacolone Retinoate (HPR) Serum · OEM/ODM
Hydroxypinacolone retinoate (HPR) is an ester of retinoic acid, brought into cosmetics as a newer-generation retinoid in the hope that it is more stable and causes fewer reactions than retinol. Its clearest documented strength is actually in the factory: in a survey of 12 commercial retinoid cosmetics, the stability of HPR stood out among the retinoids assayed. The efficacy evidence is limited: human studies used formulas combining HPR with other retinoids or peptides, or used the 9-cis isomer alone, many have authors from industry, and there is no vehicle-controlled trial of HPR on its own on the skin. At cell level, retinyl palmitate and retinyl propionate even outperformed HPR on some measures — so Butter-C does not write “HPR is stronger” or “gentler than retinol”. HPR is not tretinoin, the prescription drug banned in ASEAN cosmetics; Annex II Ref 375 reads “retinoic acid and its salts” and does not mention esters, and HPR is not named in Annexes II, III or VI (06/2026 version) — this reading should be confirmed by regulatory affairs and future annex updates should be watched. The serum is used in the evening with sunscreen during the day, in light-proof packaging, with real-time HPLC assays and a COA that includes free retinoic acid. The ingredient is not in Butter-C's standing raw-material list, so it is sourced per order. Butter-C offers turnkey OEM/ODM, from formulation and testing to the labeled finished product and notification dossier.
Formula base
HPR, an oil base or emulsion, antioxidants
HPR is highly oil-soluble and, like every retinoid, sensitive to light — the four points below decide how much HPR is still in the serum on the last day of its shelf life.
HPR — an ester of retinoic acid; confirm the isomer
According to PubChem: hydroxypinacolone retinoate (INCI: Hydroxypinacolone Retinoate), CAS 893412-73-2, C26H38O3, molecular weight about 398.6, highly lipophilic (XLogP 7.8); an ester of retinoic acid and 1-hydroxy-3,3-dimethyl-2-butanone, recorded in PubChem as the all-trans form. Some sources describe HPR as an ester of 9-cis retinoic acid (Veraldi 2015), and there is a separate study of “9-cis HPR” (Hu 2026) — so the COA must state the isomer.
Sourced per order, COA mandatory
HPR is not in Butter-C's standing raw-material list. The material may come pure or as a ready-made solution (PubChem's synonym list includes “Hydroxypinacolone Retinoate 10%”); the COA must state the actual HPR content, the isomer, any carrier (listed in the ingredient declaration) and free retinoic acid. All concentration calculations use actual HPR, not the % of the raw-material solution.
Anhydrous oil base or the oil phase of an emulsion
Being highly lipophilic, HPR is dissolved in an oil base (Caprylic/Capric Triglyceride, Squalane, jojoba oil) or in the oil phase of a light emulsion, added during cool-down, handled under reduced light and with minimal air contact — inferred from data showing that light degrades retinoids more than heat (Temova Rakuša 2021). HPR is an ester with no free acid group; we have no verified source for an optimal pH range for the emulsion version.
Antioxidants, chelation and supporting humectants
Tocopherol, BHT (Annex III Ref 342: max 1% for “Other leave-on and rinse-off products”, including any amount already in raw materials) and Disodium EDTA in water-containing versions are standard practice with retinoids; their effect must be shown by assaying HPR over time. Glycerin, Panthenol and Sodium Hyaluronate in the emulsion version give a moist feel and support tolerance.
Key technical points
Stability, free retinoic acid, concentration and regulation
More stable in the survey — still needs real-time assays
A survey of 16 retinoid derivatives in 12 commercial cosmetics: content fell 0–80% after 6 months at 25 °C and from 40% to complete loss at 40 °C; light caused more degradation than heat; among the retinoids studied, the stability of HPR was the standout. The authors concluded that stability depends on the formulation and should be assessed by real-time studies rather than accelerated testing alone (Temova Rakuša 2021). Packaging: airless bottle, aluminum tube or light-proof bottle; no wide-mouth jars or clear bottles without a carton.
Free retinoic acid on the COA
A quality-control survey of commercial retinoid cosmetics detected retinoic acid — a substance banned in cosmetics — in two products, and many products contained a retinoid type or amount that did not match the label; the team used HPLC-UV for assays and LC-MS to confirm the structure of HPR (Temova Rakuša 2021). Because HPR is an ester of retinoic acid, Butter-C requires the raw-material COA to include free retinoic acid.
Concentration: few published figures
Concentrations in human studies: 0.03% of the 9-cis HPR isomer (Hu 2026) and 0.1% HPR in a gel combined with 1% retinol and 2% papain (Veraldi 2015 — people with acne, a medical context); 0.025–1% in mice (Wu 2026). We have no verified source for typical market use levels; the actual level follows the supplier's TDS and is finalized by stability and tolerance testing on the finished product.
Regulatory: not named in ASEAN; EU entry 376 does not include HPR
Hydroxypinacolone retinoate (CAS 893412-73-2) is not named in ASEAN Annexes II, III or VI (06/2026 version) — Butter-C has re-checked the annex files; this does not mean “unrestricted use”: the safety of the chosen level must be demonstrated in the PIF. Annex II Ref 375 bans “Tretinoin (INN) (retinoic acid and its salts)” — the entry names the acid and its salts, not esters; HPR is an ester of retinoic acid, so the reading “outside the banned entry” needs regulatory confirmation and annex updates should be watched. Regulation (EU) 2024/996 (Annex III entry 376) restricts only retinol, retinyl acetate and retinyl palmitate and does not mention HPR; if a formula for the EU also contains those three, that part is subject to the retinol-equivalent limits and the vitamin A warning.
Three formulation directions
Three styles of HPR serum
Anhydrous oil-based HPR serum
HPR dissolved in Caprylic/Capric Triglyceride and Squalane with Tocopherol and BHT. With no water phase it needs no preservative system for water, but microbiology is still checked and oil oxidation monitored. For normal to dry skin, with a short ingredient list.
Light-emulsion HPR serum
HPR in the oil phase of a thin oil-in-water emulsion (Cetearyl Olivate, Cetearyl Alcohol) with Glycerin, Panthenol and Sodium Hyaluronate. Lighter than the oil version; HPR stability must be shown by real-time HPLC, a preservative challenge test to ISO 11930 and emulsion stability monitoring.
Low-level, fragrance-free HPR serum for first-time retinoid users
HPR at a low level per the TDS in an oil base with Simmondsia Chinensis Seed Oil and Tocopherol, fragrance-free. The label says to use it a few nights a week and build up according to tolerance; “suitable for first-time retinoid users” is only written after tolerance testing on the finished product itself.
How it differs from our other pages
The retinol serum uses the alcohol form of vitamin A and the EU 0.3% benchmark; the retinal serum uses the aldehyde form with the 0.05–0.1% range tested in humans; the bakuchiol serum uses a non-retinoid active; the night cream is a rich cream base that may contain a retinoid. This page is for a serum featuring HPR, built around its isomer, stability, free retinoic acid and the evidence limits of this ingredient.
Parameters we monitor
What the R&D lab measures on every sample
These are the parameters Butter-C tracks during formula development and scale-up. Specific limits are agreed with you on the approved sample and then written into the product's in-house specification.
- Incoming raw material file
- CAS, actual HPR content, isomer, free retinoic acid, carrier, appearance, manufacturing date and the supplier's storage conditions.
- HPR assay
- HPLC at the start and at real-time stability time points at room temperature; accelerated data for reference only.
- Appearance, color & odor
- Compared with the reference sample across stability time points; yellowing or a rancid oil odor means the content should be assayed again.
- Light exposure in the final pack
- Light-exposure test in the exact bottle or tube to be used; HPR content compared before and after.
- pH & viscosity
- For the emulsion version: no verified optimal pH range exists for HPR, so the pH is set on the sample through a stability study with assays; pH drift, viscosity and separation are tracked.
- Microbiology & preservative challenge
- Tested at a GLP / ISO 17025-accredited laboratory; water-containing versions get a preservative efficacy (challenge) test to ISO 11930 on the final formula; anhydrous versions are still tested for microbiology.
- On-skin assessment
- Tolerance testing on the finished product; to claim “skin looks smoother and more even-toned”, measure it on volunteers using the finished product itself.
- Packaging compatibility
- Filled into the exact airless bottle or tube to be used; seal integrity, evacuation and material odor are checked.
Claims
Claims matched to the evidence for HPR
Wang 2023: 42 Chinese women used a serum combining HPR with retinyl propionate (5:9 by weight) for 8 weeks, with improvements from baseline in wrinkles 8.3%, smoothness 11.9%, transepidermal water loss 25.7%, elasticity R2 14.5% and R5 22.6%; the abstract does not describe a vehicle group; some authors are from industry. Hu 2026: split-face, single-blind, 31 Chinese women, 0.03% 9-cis HPR versus 0.3% retinol once daily for 4 weeks; the authors describe “comparable or greater” improvements versus retinol in wrinkles, elasticity, hydration, dermal density and radiance, with no irritation observed — the abstract reports no equivalence testing; some authors are from industry. Kruger 2025: 71 women, an HPR + peptide serum twice daily for 16 weeks (42 people) versus a single fractional CO2 laser session (29 people), expert grading; the abstract gives no concentration and does not state randomization; most authors are from a cosmetics company. At cell level at the same 5 µg/mL concentration, retinyl palmitate and retinyl propionate outperformed HPR and retinol on antioxidant activity and reduced matrix breakdown (Shu 2024). Studies in people with acne (Veraldi 2015 and other combination formulas) are a medical context. Level of evidence: limited. The wrinkle results are described to help you understand the ingredient; Annex 03-MP of Circular 06/2011/TT-BYT does not accept claims of preventing, reducing or reversing age-related changes, so the label uses only the cosmetic-level statements below.
Helps skin look smoother and more even-toned (to be tested on the finished product)
Basis: the study data above (all combination formulas or the 9-cis isomer) and assessment on volunteers using the finished product itself. Instead of: anti-aging, erases wrinkles, rejuvenates, regenerates skin, boosts collagen.
Night-time skin care; use sunscreen during the day (directions for use)
Retinoids in general are degraded by light (Temova Rakuša 2021), and retinoid products come with a daytime sunscreen recommendation. Instead of: use day and night without sunscreen.
Contains hydroxypinacolone retinoate — a retinoid
State the INCI Hydroxypinacolone Retinoate correctly; state the % only when the assay holds to the end of shelf life, calculated as actual HPR; no conversion to “% retinol”. Instead of: stronger than retinol, gentler than retinol, as strong as tretinoin, prescription retinoid, replaces tretinoin, drug-like claims about acne or melasma.
Directions: start a few nights a week, a small amount on dry skin
A 24-hour patch test in 33 people: the serum combining HPR with retinyl propionate caused no adverse reactions, while retinol at the same concentration caused more (Wang 2023, some authors from industry) — a short patch test of one combination formula, not evidence of “non-irritating”. In a gel combining 0.1% HPR with 1% retinol, 15.3% of users had mild to moderate local side effects such as dryness, peeling, redness and burning (Veraldi 2015). Do not apply at the same time as high-strength AHAs or BHAs — use them at different times; do not use alongside prescription retinoid medicines unless a doctor advises it; if irritation persists, stop and see a dermatologist. Instead of: non-irritating, daily use from day one, suits every skin.
Note for pregnant and breastfeeding women
HPR is a derivative of retinoic acid. Data on safety during pregnancy and breastfeeding are insufficient — the label advises pregnant and breastfeeding women to ask a doctor before use and not to use it on their own initiative. Instead of: safe for expectant mothers.
Manufacturing specifications
Capabilities
- Texture
- Clear oil serum, pale yellow from the raw material, or a light off-white emulsion.
- Packaging format
- Airless bottle, aluminum tube or light-proof bottle. Volume agreed when choosing packaging.
- Minimum order quantity
- Agreed per order — depends on the formula direction, packaging format and raw-material lot.
- Testing
- Tested at a GLP / ISO 17025-accredited laboratory, certificates of analysis delivered with every batch; HPR assayed according to the stability plan.
- Documentation
- Product Information File (PIF) and cosmetic product notification dossier prepared by Butter-C, with the HPR raw-material COA (isomer, free retinoic acid), stability data and the safety assessment for the chosen HPR level.
- Packaging
- Label design, printing and packing run in parallel with formulation; the label includes evening use, daytime sunscreen and the pregnancy note.
Suggested product concept
An oil-based HPR serum for first-time retinoid users
One product concept to help you picture the result; not a ready-made product for sale. The actual formula is built around your brand's positioning and price range.
HPR as the featured ingredient
Sourced per order, COA for content, isomer and free retinoic acid; level per the TDS, HPLC assay at the start and according to the real-time stability plan.
Anhydrous oil base with antioxidants
Caprylic/Capric Triglyceride, Squalane, Tocopherol, BHT within Annex III Ref 342.
Fragrance-free
Removes one more source of irritation for first-time retinoid users; tolerance tested on the finished product.
Light-proof airless bottle
The label lists the INCI Hydroxypinacolone Retinoate and every component of the raw material, evening use, a few nights a week at first, daytime sunscreen and the pregnancy note; claims stop at “helps skin look smoother and more even-toned” after testing on the finished product.
Customization options
What you can specify
The same product type can serve very different customers. Tell us your requirements in the areas below and our pharmacists will build the matching formula.
HPR level
Set from the TDS and from tolerance and stability testing on the finished product; human data exist only for 0.03% (9-cis isomer) and 0.1% (combination gel) — higher levels need a separate safety rationale in the PIF.
Oil or emulsion base
An anhydrous oil base for stability and a short ingredient list; a light emulsion for a thinner feel, at the cost of more thorough proof of HPR stability.
Combining other retinoids
Human studies often combine HPR with retinyl propionate, retinol or retinyl palmitate; each added retinoid adds to the potential for dryness and peeling and needs its own tolerance testing. For the EU: retinol, retinyl acetate and retinyl palmitate count toward the entry 376 limits with the vitamin A warning.
Supporting ingredients
Humectants and soothing agents (Panthenol, Allantoin, Sodium Hyaluronate in the emulsion version); no high-strength AHAs, BHAs or azelaic acid (banned in ASEAN) in the same bottle.
Fragrance and packaging
Fragrance-free recommended; airless bottle, aluminum tube or light-proof bottle — clear packaging without a carton and wide-mouth jars are not suitable for retinoids.
Companion products
A daytime sunscreen and a gentle moisturizer in the same line to sell as a set, helping users follow the directions.
Further reading
Related topics
Hydroxypinacolone retinoate (HPR) in cosmetics
Mechanism, stability, human evidence, ASEAN and EU regulation (in Vietnamese).
Retinol in cosmetics
General background on retinoids, the EU vitamin A rules and low-irritation use (in Vietnamese).
Light and the skin
Why retinoid products come with daytime sunscreen directions (in Vietnamese).
Retinol serum OEM/ODM
Another direction: the alcohol form of vitamin A, levels set against the EU benchmark.
Retinal serum OEM/ODM
Another direction: the aldehyde form of vitamin A, the 0.05–0.1% range tested in humans.
Bakuchiol serum OEM/ODM
Another direction: a plant-derived active that is not a retinoid.
How we work
From idea to finished batch
Eight steps and three milestones signed off by both sides: approved sample, notification number, finished batch. Step-by-step details →
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