LORs - pls help me pick

[pshah05]

hey y’all

I’m applying this coming fall (2025) but wanted to ask this right off the bat to figure it out. Most of my undergraduate research experience was during the height of covid/ immediately after so I have a complicated relationships hahah. As for my research experiences, don’t worry, I have more but not with anyone I’d be comfortable asking. But essentially who should I choose to write my letters? Here are my options:

I have a postdoc i worked closely with for 2 years and would happily write me a letter because she believed in my ability and taught me nearly everything I know. That research led to a paper w my name that is also in review. The PI of this lab doesn’t like me and I don’t know if I want him writing my letter but I was thinking of asking him to co-sign? Is that a good idea?

An undergrad professor who I didn’t do research with but had me for an upper div elective and capstone class. I aced both and we had a great relationship! It’s been a while since we’ve chatted though so I sent her a proactive email just to reach out and see if she’ll even remember me.

An undergrad professor who I didn’t have for class but was in her research lab during covid. I didn’t produce any meaningful data but helped her establish the beginnings of her lab and she taught me a few skills like perfusions and animal handling I still use at my current job. She also had a journal club type thing over zoom where I presented several papers from the field. She’s explicitly said before that she’d be happy to write me a letter in the future BUT i don’t know how strong it will be.

My current main co boss (I have two) in biotech industry who i’ve been working with for a year now (she has a PhD) and can speak to my research abilities, competency, future goals etc. I’m sure she’d write me a strong letter and I’m 99.9999% sure I should ask her. I could also ask my other boss who also holds a PhD.

A past PI but I only worked for her for 5 months before getting the job I have now. Again I didn’t produce any meaningful data with her and we had a pleasant relationship (though I wouldn’t call it close). She knows I’m capable of cell culture, troubleshooting problems with our cells, and learning quickly. I also think she’s maybe able to get a picture of my work ethic (I worked on weekends often bc cells)! Again I don’t know if she can write me a strong letter.

Thank you for reading all of this and for helping me weigh this out! I really appreciate it