I'm here to tell you the bull case for Lilly’s Foundayo rests on an unspoken assumption: **nobody in the target demographic is having sex.** Sounds crazy?
**The facts:**
Oral Wegovy seems to be more effective than Foundayo. \~14% vs \~11% weight loss at max dose in a cross-trial comparison.\[1\]
The injectable GLP-1 market is kinda old people. These are postmenopausal women and middle-aged dudes with metabolic syndrome. They signed up for needles, cold chain, and insurance fights. They have demonstrated they don't give a shit about friction.
The pill market is different. Younger. Lower BMI. Price-sensitive. Needle-averse. Convenience-maximalist. This is where Foundayo's growth has to come from.
Here's the kicker I suspect nobody is pricing in. Foundayo's FDA label requires women on oral birth control to either switch to non-oral contraception OR use condoms for 30 days after starting AND 30 days after each dose escalation. That's 3-6 months of continuous backup contraception to reach max dose.\[2\]
Oral Wegovy has no such warning. Semaglutide was directly studied for oral contraceptive interaction. No clinically meaningful effect. Zero friction, so to say.
**The thesis:**
Imagine you're a 32-year-old woman on the pill. You want to lose weight. You have two options:
Oral Wegovy: Take it in the morning, wait 30 min to eat (you already skip breakfast anyway). \~14% weight loss. No change to your birth control.
Foundayo: Take whenever you want. 11% weight loss. Also: use condoms for the next 3-6 months. Every time your doctor bumps your dose, the 30-day clock resets. Tell your boyfriend that his cucumber will be residing in a plastic bag for 3-6 months.
**Which one do you pick?**
This is not a hard question. This is the easiest A/B test in pharma. Lilly is saying that their products add “convenience”. However, that’s only if you are not on the pill.
I spun up a Jupyter Notebook, found some demographic data (birth control usage\[3\], age and gender of the patients\[4\]), and did some crude calculations:
My best guess is that 9-14 percent of the potential patients will be somewhat affected when you factor in that the mean age of the **NEW** users will be lower for the pill (I used 3 to 8 years in my simulated population). It's hard to say how much but the effect could very well be very real (but I l have tried to be conservative in my estimations).
As I said: For the injectables this is not that big of a problem - the customers have demonstrated that they can tolerate the friction and they are older (i.e. not on birth control). The birth control problem is only a problem for the marginal costumer.
But when the potential costumer base becomes younger, then the effects of this problem rises **rapidly** (that's just statistics).
The 9-14 percent is a huge number in my humble opinion… Also, I don’t factor in the narrative aspect of this problem: Lilly is trying to brand themselves as the “convenient” choice - but for women they could become the option that messes with your birth control.
**Why this isn't priced in:**
Clinical analysts read efficacy tables. Commercial analysts build models. Nobody at a bank has the job of considering the sexual aspect. Maybe they should hire a Chief Friction Analyst?
The birth control warning is in the label. The efficacy gap is in the trials. It's all public.
We now have the first indication that LLY is not selling as many pills as NVO. \~20 percent of the sales that the Wegovy pill made for a full week.\[5\]
**Catalyst:**
Q1 earnings April 30. Watch the early Foundayo script data. If Novo's oral semaglutide is specifically winning the young female segment - not just winning in aggregate - the thesis plays out over the next 2-3 quarters.
Position: Long NVO. No position in LLY.
**Sources:**
\[1\]: [https://www.drugs.com/medical-answers/foundayo-wegovy-how-compare-weight-loss-3582233/](https://www.drugs.com/medical-answers/foundayo-wegovy-how-compare-weight-loss-3582233/)
\[2\]: [https://www.drugs.com/medical-answers/take-foundayo-birth-control-pills-3582165/](https://www.drugs.com/medical-answers/take-foundayo-birth-control-pills-3582165/)
\[3\]: [https://www.kff.org/womens-health-policy/contraceptive-experiences-coverage-and-preferences-findings-from-the-2024-kff-womens-health-survey/#2e2b05b0-78bf-43e8-829b-05128409c693](https://www.kff.org/womens-health-policy/contraceptive-experiences-coverage-and-preferences-findings-from-the-2024-kff-womens-health-survey/#2e2b05b0-78bf-43e8-829b-05128409c693)
\[4\]: [https://www.kff.org/public-opinion/poll-1-in-8-adults-say-they-are-currently-taking-a-glp-1-drug-for-weight-loss-diabetes-or-another-condition-even-as-half-say-the-drugs-are-difficult-to-afford/](https://www.kff.org/public-opinion/poll-1-in-8-adults-say-they-are-currently-taking-a-glp-1-drug-for-weight-loss-diabetes-or-another-condition-even-as-half-say-the-drugs-are-difficult-to-afford/)
\[5\]: [https://www.reuters.com/business/healthcare-pharmaceuticals/lillys-obesity-pill-hits-nearly-4000-prescriptions-second-week-after-launch-2026-04-24/](https://www.reuters.com/business/healthcare-pharmaceuticals/lillys-obesity-pill-hits-nearly-4000-prescriptions-second-week-after-launch-2026-04-24/)