Borage seed oil: SAP value and fatty acids
Borage seed oil has a saponification value of 187.8 mg KOH/g. One gram needs 0.134 g of sodium hydroxide (NaOH) for bar soap or 0.188 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.133879 g per g oil
- SAP, KOH
- 0.1878 g per g oil
- Saponification value
- 187.8 mg KOH/g
- INCI name
- Borago Officinalis Seed Oil
Example: 100 g of Borage seed oil with no superfat needs 13.4 g of 100% NaOH, or 18.8 g of 100% KOH. A 5% superfat uses 5% less.
In soap
Its main fatty acids in our cited profile are linoleic (35.9%) and oleic (21.3%). The eight fatty acids used in soap-quality scores make up 91.3% of the profile.
On its own it scores 17 for hardness, 0 for cleansing and 75 for conditioning, with a saturated : unsaturated split of 17 : 75.
Fatty-acid profile
| Fatty acid | % of fatty acids | Counts toward |
|---|---|---|
| lauric | 0% | hardness, cleansing, bubbly lather |
| myristic | 0% | hardness, cleansing, bubbly lather |
| palmitic | 10.7% | hardness, creamy lather |
| stearic | 6% | hardness, creamy lather |
| ricinoleic | 0% | conditioning, bubbly and creamy lather |
| oleic | 21.3% | conditioning |
| linoleic | 35.9% | conditioning |
| linolenic | 17.4% | conditioning |
Basis: Peer-reviewed GC of borage seed oil (Antioxidants 2025, Table 1); linolenic = GLA + ALA.
Soap-quality scores (this oil alone)
| Hardness | 17 |
|---|---|
| Cleansing | 0 |
| Conditioning | 75 |
| Bubbly lather | 0 |
| Creamy lather | 17 |
Each score adds up certain fatty acids, the way Soap Ledger scores a whole recipe. They are for comparing recipes; they don't predict how a bar will feel, and they say nothing about safety or skin.
Sources
SAP value: 187.8 mg KOH/g (Median of sources), from Dash B. et al. (2026) Cold pressed oils: a systematic review on physicochemical properties, nutritional composition and pharmacological activities. Frontiers in Nutrition. doi:10.3389/fnut.2026.1747029, Frontiers (open access, peer-reviewed review). Printed value: 184–195 mg KOH/g.
Published values we checked:
- 175 - 196 mg KOH/g — From Nature With Love (soap/cosmetic supplier)
- 185 mg KOH/g — The Soapery (UK soap supplier)
- 190 mg KOH/g — The Soapery (UK soap supplier)
- NaOH 0.1339 / KOH 0.1886 g alkali per g oil — Certified Lye
- 184–195 mg KOH/g — Frontiers (open access, peer-reviewed review)
Fatty acids: Fatty Acid Profile and Some Useful Biological Aspects of Borage, Calophyllum, and Prickly Pear Seed Oils. Antioxidants 14(6):661 (2025), MDPI.
NaOH and KOH values are converted from mg KOH/g with the molar masses 39.997 and 56.106 and rounded to 6 decimals, exactly as in the Soap Ledger app. Real oils vary by origin, grade and lot: check your supplier's certificate of analysis. Verify every weight before you make this, and follow lye safety. Not a safety or compliance certification.
Last updated .