External CondomvsVaginal pH Modulator

A side-by-side comparison of two birth control methods — efficacy, cost, how they work, and who shouldn't use them.

Side-by-side comparison

Method	External Condom A non-hormonal barrier method that also lowers the risk of STIs, available over the counter.	Vaginal pH Modulator A prescription gel used before sex that keeps vaginal pH acidic to disable sperm.
Efficacy	87% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.	86.3% typical use Least effective: under 90 out of 100 people successfully prevent pregnancy per year.
Cost	$0.5–$3 /per unit Insurance: Varies	$0–$400 /per package Insurance: Usually
Duration	Single use	Single use (effective for 1 hour)
Reversibility	Reversible	Reversible
STI Protection	Yes	No
How it works	A physical sheath worn over the penis that blocks semen from entering the vagina and reduces skin-to-skin contact that transmits STIs.	A gel containing lactic acid, citric acid, and potassium bitartrate maintains an acidic vaginal pH that disables sperm and reduces their motility. It also acts as a physical barrier to sperm movement.
Prescription	OTC No prescription / OTC	Required Prescription required
Side effects	Rare local irritation from latex or lubricants	Vaginal burning or irritation Increased risk of urinary tract infection Rare allergic reaction
Who shouldn't use this	Known allergy to latex (use polyisoprene or polyurethane instead)	Recurrent UTIs or urinary tract abnormalities (FDA label says avoid use)

Key differences

External Condom is more effective (87% vs 86.3% typical use). External Condom duration: Single use. Vaginal pH Modulator duration: Single use (effective for 1 hour). Only External Condom protects against STIs. Vaginal pH Modulator requires a prescription; External Condom does not. External Condom: costs $0.5–$3 per unit. Vaginal pH Modulator: costs $0–$400 per package.