Some types of progestins can have androgenic effects and some women on birth control pills with an older formulation can find hair loss or hirsutism is actually promoted by the pill. Synthetically made progestins in birth control pills are not the same as naturally produced progestins like progesterone. Some synthetic progestins' molecular conformation mean they are the right shape to fit into androgen receptors in hair follicles and elsewhere and elicit a response.
Some synthetic progestins are structurally very similar to testosterone and/or estrogen so their androgenic or antiandrogenic effects supplement an individual's natural hormone production levels. The response is quite variable from person to person. While some people have excess hair growth from using the pills others may develop hair loss.
I assumed the older verisons of BC pills would have this effect. They are normally also the ones given out at free/low income medical clinics.
Least likely to cause hirsutism to most likely to cause hirsutism-
Desogen, Ortho-Cept, Ortho-Cyclen, Ortho Tri-Cyclen, Micronor, Nor-Q D, Ovcon-35, Brevicon/Modicon, Ortho Norvum 7/7/7, Ortho Novum 10-11, Tri-Norinyl, Norinyl and Ortho 1/35, Demulen 1/35, Triphasil/Tri-Levien, Nordette, Lo/Ovral, Ovrette, Ovral, Loestrin1/20, Loestrin 1.5/30.
Listed below are the best birth control pills for women who want to avoid acne, alopecia, or hirsutism: Desogen, Ortho-Cept, Ortho-Cyclen, Ortho-Tri-Cyclen, Brevicon, Modicon, Ovcon-35, and Demulen-35.
Newer oral contraceptive formulations containing progestins with minimal androgenic potential should have the generic names norgestimate, desogestrel, or gestodene on the side of the packet. Norgestimate is generally regarded as the least androgenic progestin found in contraceptive pills.