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From reality TV star baby announcements to mysteriously popular eggs, Instagram's power to reach millions cannot be overstated. It's no surprise that businesses have attempted to capitalize on that reach by partnering with “influencers,” or users with thousands or millions of followers, to advertise their products. These partnerships are often lucrative for the influencers: Kim Kardashian, for example, reportedly charges more than $250,000 for an Instagram post. But when pharmaceutical companies and health startups use influencer-advertising, do some details get lost in the posting?

According to Vox, the answer is yes. And when it comes to regulating these ads, government agencies are still vague on setting boundaries.

The FDA mandates that ads for medical devices and pharmaceuticals must include possible risks of use as well as rewards, which is why television ads contain all those disclosures. But when it comes to social media, the FDA seems a little behind the times. According to Vox, the most recent FDA guidance for social media advertising was published in 2014 and doesn't even mention Instagram. The FTC's guidelines have been updated within the past two years. Both agencies recommend more disclosure in posts, but neither say how far into a post is best for that disclosure to be recognized.

Neither the FDA nor the FTC “attempt to survey all influencers or influencer post,” according to the FTC Advertising Practices Division. The agencies instead rely on consumers to flag non-compliant ads. Influencers are not likely to face the kinds of legal repercussions that a drug company would for leaving out information about a medication or a device. Consequences to the influencers would be at the discretion of the companies they've been contracted to represent.

In spite of hashtags like #sponsored and #partner, Instagram ads don't look like typical ads. That's part of their appeal, particularly to millennials. A survey by Yahoo says millennials will have close to $1.4 trillion in spending power by 2020, and because of their willingness to engage with and share content, that makes them a very desirable demographic.

British blogger Louise Roe has over 700,000 followers on Instagram and a paid partnership with Celgene, a biotech company that manufactures a psoriasis medication called Otezla. Roe has psoriasis herself, but Vox points out that apart from an acknowledgement of that paid partnership, there's no sign of her affliction on her posts. There are also no details about how Celgene won't necessarily work for someone the way it seems to work for Roe, but there are accompanying hashtags that mark such a post as an #Ad.

Travel blogger Lesley Murphy has a genetic mutation that increases her risk of certain cancers. She uses Instagram to talk to her 412,000 followers about health issues and even documented her preventive double mastectomy on the platform. She is also advertising ReSensation, a surgical technique that may help women who have had breast reconstruction retain some or all sensation in their breasts. Her posts are also hashtagged #partner to note that she's being paid for her advertisement, but she hasn't actually undergone the ReSensation technique herself. An Instagram post directs readers to her blog, where she not only discloses that she hasn't had the surgery but also that it would be incompatible with her implant reconstruction. Vox reports that the link to her blog does not take a reader directly to that information, making it difficult to find.

According to a report in the Journal of Medical Internet Research, one in three U.S. consumers consult social media for health-related matters. Instagram is projected to have more than 1.1 billion users in 2019.