Tips for a beginner lactic acid serum?
Hi everyone!!
I think this forum is a really nice idea. I’ve been getting more interested in making simple skincare formulas at home, and I thought I’d start by asking about lactic acid serum.
Does anyone have a good beginner-friendly recipe or any tips before trying to make one?
I’m especially wondering about what percentage of lactic acid is best to start with, how important the final pH is, what preservative would be suitable...
Would love to hear what has worked for other people.
Replies
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Hi and welcome, I’m really happy you started the first topic here.
Lactic acid is a nice ingredient to begin with because it is an AHA that exfoliates the skin, but it is usually considered gentler than glycolic acid because of its larger molecule size. It can help with dull skin, uneven texture, roughness, and mild dryness, and it also has some humectant properties, so it can support hydration while gently renewing the skin.
For a beginner serum, I would personally start low, around 3–5% lactic acid, rather than jumping straight into stronger percentages. Around 2–5% is usually a gentle starting range, 5–8% is more active, and 10% or higher is better left for people who already understand acids and pH adjustment.
The final pH is very important with lactic acid because it affects both how effective and how irritating the serum can be. A common target would be around pH 3.5–4.0. If the pH is too high, the acid may not exfoliate properly, and if it is too low, it may be too irritating.
Since this would be a water-based serum, you also need a suitable broad-spectrum preservative that works at a low pH. Cosgard/Geogard 221, Geogard ECT, or Euxyl PE 9010 can be options, but always check the supplier’s instructions, usage rate, and pH compatibility.
I’d also recommend making a small test batch first, patch testing, using it at night, and wearing sunscreen during the day, because AHAs can make the skin more sun-sensitive.