PSA: salicylic acid might be why you're a slow gainer or non-responder

This is some basic information that I don't see mentioned very often, and is something you guys should be aware of.

TL;DR Oral salicylic acid (aspirin) is probably inhibiting your gains. Topical salicylates may or may not inhibit your gains.

More commonly known is that tretinoin (and other retinoids but to a lesser degree) enhances minoxidil response by upregulating follicular sulfotransferase enzymes and can turn a nonresponder into a responder. Especially if you're only applying once per day since minoxidil & tretinoin once-daily is as effective as minoxidil by itself twice-daily.

Less commonly known is that sulfotransferase activity is significantly inhibited by salicylic acid this of course includes a very common oral salicylate, aspirin- but applies to all salicylates in varying degrees. Salicylic acid (sometimes listed only as BHA) is found in an insane amount of skincare, acne and hair products. Methyl salicylate is another one to look out for, commonly found in beard/hair oils and balms that are based on wintergreen, which is a source of methyl salicylate.

And before anyone tries to argue that topical products containing salicylic acid won't increase blood plasma concentration to any substantial degree: there have been dozens of cases of toxicity from topical use of salicylic acid. Be especially mindful if you microneedle that absorption of salicylic acid is greatly increased through damaged skin. I'm not telling you that because it's dangerous, but because it could slow your progress.

The half-life is dose dependent but can be as long as 12 hours, so if you're routinely using products that contain salicylates— oral or topical doesn't matter, be aware that you might be slowing down your gains or that it might even be the reason why you're not seeing progress.